Fair Value Hierarchy of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Feb. 28, 2020	Feb. 22, 2019	Feb. 23, 2018	Feb. 24, 2017
Assets, Fair Value Disclosure [Abstract]
Restricted Cash		$ 3.5	$ 2.5	$ 2.5
Foreign Currency Contract, Asset, Fair Value Disclosure	$ 1.2	3.9
Liabilities, Fair Value Disclosure [Abstract]
Foreign Currency Contracts, Liability, Fair Value Disclosure	(0.5)	(0.5)
Fair Value, Recurring [Member]
Assets, Fair Value Disclosure [Abstract]
Cash and Cash Equivalents, Fair Value Disclosure	541.0	261.3
Restricted Cash	6.1	3.5
Assets, Fair Value Disclosure	550.4	272.6
Liabilities, Fair Value Disclosure [Abstract]
Foreign Currency Contracts, Liability, Fair Value Disclosure	(0.5)	(0.5)
Liabilities, Fair Value Disclosure	0.5	0.5
Fair Value, Recurring [Member] | Foreign Exchange Contract [Member]
Assets, Fair Value Disclosure [Abstract]
Foreign Currency Contract, Asset, Fair Value Disclosure	1.2	3.9
Fair Value, Recurring [Member] | Auction Rate Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	2.1	3.9
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Cash and Cash Equivalents, Fair Value Disclosure	541.0	261.3
Restricted Cash	6.1	3.5
Assets, Fair Value Disclosure	547.1	264.8
Liabilities, Fair Value Disclosure [Abstract]
Foreign Currency Contracts, Liability, Fair Value Disclosure	0.0	0.0
Liabilities, Fair Value Disclosure	0.0	0.0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Foreign Exchange Contract [Member]
Assets, Fair Value Disclosure [Abstract]
Foreign Currency Contract, Asset, Fair Value Disclosure	0.0	0.0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Auction Rate Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0.0	0.0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Cash and Cash Equivalents, Fair Value Disclosure	0.0	0.0
Restricted Cash	0.0	0.0
Assets, Fair Value Disclosure	1.2	3.9
Liabilities, Fair Value Disclosure [Abstract]
Foreign Currency Contracts, Liability, Fair Value Disclosure	(0.5)	(0.5)
Liabilities, Fair Value Disclosure	0.5	0.5
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Foreign Exchange Contract [Member]
Assets, Fair Value Disclosure [Abstract]
Foreign Currency Contract, Asset, Fair Value Disclosure	1.2	3.9
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Auction Rate Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0.0	0.0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Cash and Cash Equivalents, Fair Value Disclosure	0.0	0.0
Restricted Cash	0.0	0.0
Assets, Fair Value Disclosure	2.1	3.9
Liabilities, Fair Value Disclosure [Abstract]
Foreign Currency Contracts, Liability, Fair Value Disclosure	0.0	0.0
Liabilities, Fair Value Disclosure	0.0	0.0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Foreign Exchange Contract [Member]
Assets, Fair Value Disclosure [Abstract]
Foreign Currency Contract, Asset, Fair Value Disclosure	0.0	0.0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Auction Rate Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value Disclosure	$ 2.1	$ 3.9	$ 3.5